• 한국세라믹학회지
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• 제42권10호
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• pp.691-697
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• 2005

Porous ceramics which have closes pore were fabricated by heat treatment at 100$\∼$ 600$^{\circ}C$ for 30 min using dried water glasses with 25, 35, and 45 wt$\%$ water contents. Size and distribution of the closed pore were varied depending on the water contents and heat treatment temperature. The expansion procedure could be distinguished by two stages. The frist stage occurred around loo$\%$ due to the evaporation of water and the second stage occurred at 200$\∼$400$^{\circ}C$ due to the decomposition of Si-OH compounds. The specimen was not expanded successfully because of the softening of the dried water glass at 500$\∼$600$^{\circ}C$.

• Korean Membrane Journal
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• 제10권1호
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• pp.33-38
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• 2008

In this study periodic water-back-flushing using permeate water was performed to minimize membrane fouling and to enhance permeate flux in tubular ceramic micro filtration system for Gongji stream water treatment in Chuncheon city. The filtration time (FT) 2 min with periodic 6 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_0$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume ($V_T$) of 7.44L. Also in the results of BT effect at fixed FT 10 min, BT (back-flushing time) 20 sec showed the lowest value of $R_f$ and the highest value of $J/J_0$, and we could be obtained the highest $V_T$ of 8.04 L. Consequently FT 10 min and BT 20 sec could be the optimal condition in Gongji stream water treatment. Then the average rejection rates of pollutants by our tubular ceramic MF system were 93.8% for Turbidity, 20.7% for $COD_{Mn}$, 39.2% for $NH_3$-N and 31.5% for T-P.

• 한국작물학회지
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• 제44권4호
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• pp.321-329
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• 1999

The effect of water deficits on soybean [Glycine max (L.) Merr.] could appear on seed quality through changes of morphological plant characteristics. Two Korean genotypes, Hwangkeum (determinate growth habit) and Muhan (indeterminate growth habit), were used to examine the influences of treatment stage and method of water deficit during reproductive growth period on yield and seed quality of soybean. Water deficit at R5 or R6 stages was as damaging to seed quality as double water-deficit treatments at R2+R5 or R2+R6. However, seed from double water-deficit treatment tended to have lower oxidation-reduction potential compare to the corresponding single water-deficit treatment. In comparison with Muhan, Hwangkeum had significantly greater oxidation-reduction potential value. Seed yield per plant in both genotypes depended greatly on seed yield of branches. However, the proportion of number of branch seed to total seed umber in Hwangkeum was increased as the water deficit was applied during later reproductive stage, whereas, in Muhan the proportion was lower. Water-deficit treatments including the single and double water-deficit treatments and non-stressed treatment were able to be classified into five groups for Hwangkeum and four groups for Muhan based on the influences on yield components, number of pod, number of seed, and single seed weight, using principal component analysis. In both genotypes, R2+R5 water-deficit treatment decreased number of pod and seed, but increased single seed weight. On the contrary, R6 or R2+R6 stress increased the pod and seed number, but decreased single seed weight.

• 한국지반환경공학회 논문집
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• 제14권4호
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• pp.15-27
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• 2013

본 연구에서는 대구 G정수장 막여과 정수처리시설을 계획하기 위해 원수수질 처리에 적합하고 경제적인 시스템을 적용하고자 현장모형실험을 통하여 동절기를 포함한 6개월 동안의 연속운전에 따른 수량과 수질, 그리고 공정의 안정성을 평가하였다. 환경부 막여과 정수시설의 설치기준에 의해 실시된 현장모형실험에서 1계열 목표수질 검증설비와 2계열 막공정 평가설비로 나누어 2계열로 수행되었다. 공정수질은 탁도 0.03 NTU 이하로서, 증류수 수질의 탁도를 나타내었으며 먹는 물 수질기준을 모두 충족하였다. 공정운전에서 99%의 회수율로 안정된 막차압을 나타내어 공정운전에 수질 및 수온 등의 영향에 대비한 공정설계가 되었음을 확인하였다. 따라서 지속적인 기술개발을 통해 설계 및 시공 노하우에 대한 지속적인 경험이 축적되어 막여과 고도정수처리 기술에 대한 엔지니어링 원천기술을 확립하고자 한다.

• 한국발생생물학회지:발생과생식
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• 제17권3호
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• pp.289-297
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• 2013

Bisphenol A (BPA) is an estrogenic endocrine disrupter. However, depending on a way of treatment, the harmful effects of BPA have not been confirmed. Also, trans-generational effects of BPA on male reproduction are still controversial. Because the reabsorption of testicular fluid in the efferent ductules (ED) and initial segment (IS) is important for sperm maturation, the present study was designed to determine trans-generational effect of BPA administrated orally on expression of water transport-related molecules in the mouse ED and IS. Ethanol-dissolved BPA was diluted in water to be 100 ng (low), $10{\mu}g$ (medium), and $1mg/m{\ell}$ water (high). BPA-containing water was provided for two generations. Expression of ion transporters and water channels in the ED and IS were measured by relative real-time PCR analysis. In the ED, BPA treatment caused expressional increases of carbonic anhydrase II, cystic fibrosis transmembrane regulator, $Na^+/K^+$ ATPase ${\alpha}1$ subunit, and aquaporin (AQP) 1. No change of $Na^+/H^+$ exchange (NHE) 3 expression was detected. BPA treatment at medium dose resulted in an increase of AQP9 expression. In the IS, the highest expressional levels of all molecules tested were observed in medium-dose BPA treatment. Generally, high-dose BPA treatment resulted in a decrease or no change of gene expression. Fluctuation of NHE3 gene expression by BPA treatment at different concentrations was detected. These findings suggest that trans-generational exposure to BPA, even at low dose, could affect gene expression of water-transport related molecules. However, such effects of BPA would be differentially occurred in the ED and IS.

• 한국물환경학회지
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• 제27권1호
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• pp.1-8
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• 2011

네팔의 천연 수자원은 풍부한 편이나 모든 인구가 안전하고 깨끗한 식수를 공급받고 있지는 못한 상황이다. 또한, 폐수 처리에 대한 상황 역시 매우 열악한 상태라고 할 수 있다. 최근, 도시로의 인구 유입이 증가함에 따라 안전한 물의 공급 및 공중 위생에 대한 관심이 증대되고 있으나, 수인성 질환의 발병률은 여전히 높은 상황이다. 본 논문에서는 네팔의 수질 오염, 식수에서의 비소 오염, 폐수 처리, 그리고 대중의 건강에 대한 수질 오염의 영향 등에 대해 검토하였다. 또한, 폐수 처리와 연관된 규제와 관련하여 한국의 상황과 비교하여 양국의 상황을 비교 고찰하였다. 이러한 내용들에 의거하여 대중의 건강 증진을 위한 현존 문제점들의 해결 방안들을 제시하였다.

• 생물환경조절학회지
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• 제19권4호
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• pp.266-274
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• 2010

본 연구는 토마토의 토양 수분결핍조건에서의 생장과 생리적인 반응을 근본적으로 조사하기 위하여 수행되었다. 토양에 두가지 수분조건, 심한 수분결핍(-100kPa)과, 대조구인 약한 수분결핍 처리(-25kPa)는 실시간 토양수분함량을 모니터링을 할 수 있는 토양센서와 관수 모듈을 갖춘 micro-irrigation 시스템을 고안, 온실에서 유지되었다. 토양수분함량은 30일동안 변동되었으며, -25kPa로 맞춰진 처리구는 평균 -47kPa, -100kPa 처리구는 평균 -119kPa로 차이를 나타냈다. 이 두 가지 다른 토양수분상태에서 자란 식물체 사이의 생육을 비교해 본 결과 수분결핍상태(-100kPa)에서 자란 식물체가 대조구인 약한 수분결핍(-25kPa) 처리구에 비해 절간수의 차이없이 신장이 유의하게 감소하였으며 건물중의 축적은 더 높게 나타났다. 또한 건물중 당 엽면적의 차이 없이, 엽면적과 엽건중이 수분 결핍이 약한 처리구에 비해 수분결핍이 심한 처리구가 더 높게 나타났다. 이러한 생육상의 차이는 심한 수분스트레스가 엽두께의 변화없이 생체중의 증가와 엽면적 확보를 통해 토마토의 수분스트레스에 적응을 야기시킬 수 있음을 제시했다. 수분결핍에 따른 토마토 생육기간동안, 생리적변화를 조사한 결과, -100kPa 처리구에서 자란 토마토가 대조구인 -25kPa 처리구에 비해 엽의 상대수분함량의 증가와 잎의 삼투압이 낮게 나타났다. 이는 수분스트레스아래서 토마토의 더 나은 수분상태를 유지하기 위한 생리적인 적응을 설명해준다. 아울러 심한 수분스트레스는 대조구에 비해 PSII 활성과 수분활용도를 증가되었으며, 낮은 기공저항도를 나타내었다. 처리간의 광합성의 차이는 없었으며, 토마토 과실의 수와 생육량의 차이는 없었다. 이러한 결과는 토마토 'Picco'가 엽형태의 변형과 삼투압, 수분활용도와 PSII의 활성을 통해 수분결핍상태에서 적응할 수 있게 만들 능력을 보여준다. 본 연구결과에서 나타난 토마토의 수분스트레스 적응 메커니즘은 토마토의 가뭄저항성 스크린에 있어서 고려되어져야 할 것으로 보인다.

• 한국환경과학회지
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• 제24권12호
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• pp.1551-1558
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• 2015

In Korea, many drinking water treatment plants (DWTPs) have introduced and are going to introduce biological activated carbon (BAC) process to treated dissolved organic matter (DOM) in water which are difficult to control by conventional water treatment processes. Even though more decade have passed since introduced BAC in Korea, most of BAC operating method was followed to the modified sand filter operating manuals. In case of BAC backwashing, many DWTPs set the periods of backwashing about 3~5 days. In this study, we have collected data to set the proper BAC backwashing periods from both pilot-plant and real DWTPs. We had measured heterotrophic plate count (HPC), turbidity, water temperature, dissolved organic carbon (DOC) and headloss from just after backwashing to the next backwashing time for two years. Considering water quality factors, the BAC run time from backwashing to the next backwashing could extend more 30 days without water quality deterioration if the head loss do not reach the limited level which depends on each BAC facilities' condition. It means the BAC treated water could be saved in the proportion of extended the backwashing period to the existing backwashing period.

• 수도
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• 통권28호
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• pp.27-36
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• 1983

Oxidation process constitute an important and often indispensable measure in the reliable production of safe drinking water. Optimal introduction of oxidation processes into the treatment of drinking water requires an exact knowledge of the reactions taking place and of their interrelationships. It is the aim of this paper to review the necessary knowledge in summarized form.

• 환경위생공학
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• 제17권4호
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• pp.1-9
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• 2002

In order to define about concern with discharge and water-quality, it is calculated drought flow, low flow, normal flow and wet flow in Chungju watershed from flow duration analysis. Water quality modeling study is performed for forecasting at upstream of Chungju lake. It is devided method of modeling into before and after the equipment of environmental treatment institution. And it is estimated the change of water quality. Before the equipment of environmental treatment, BOD concentration is increased from 23000 to 2006 years at all site and decrease on 2012 years. The rate of increasing BOD concentration is showed height between 2000 years and 2003 years most of all site. And after the equipment of environmental treatment, it is showed first grade of BOD water quality in most of sample site beside Jucheon river. The result of water quality modeling using drought flow showed that a lot of pollution occurred. And water quality using wet flow is good, so much discharge make more improve water quality than little discharge.